Dopant Profile Changes Induced by Pulsed Laser Annealing

摘要

Secondary ion mass spectrometry (SIMS) and Rutherford ion backscattering was used to investigate the effects of pulsed laser annealing (Q switched ruby laser, 50 x 10 exp -9 sec. pulse duration time) on silicon crystals implanted by B, P, As, Sb, Cu, and Fe. The results show that B, P, As, and Sb undergo substantial redistribution in the absence of significant surface segregation during the laser annealing process. Calculations strongly suggest that the crystal can be melted to a depth of approx. 1 mu and the implanted region remains in the melted state for several hundred nanoseconds. Profiles calculated for liquid phase diffusion of the dopant are shown to be in excellent agreement with the experimental results. Arsenic profiles after laser annealing are shown to be very sensitive to the laser photon energy density. Profiles for implanted Cu and Fe show significant segregation to the surface after pulsed laser annealing and this may be related to their very low segregation coefficient from the liquid. (ERA citation 04:034297)